Improving high-resolution MR bold venographic imaging using a T1 reducing contrast agent

Abstract

Recently, a new imaging method was proposed by Reichenbach et al (Radiology 1997;204:272-277) to image small cerebral venous vessels specifically. This method, referred to as high-resolution blood oxygen level-dependent venography (HRBV), relies on the susceptibility difference between the veins and the brain parenchyma. The resulting phase difference between the vessels and the brain parenchyma leads to signal losses over and above the usual T2* effect. At 1.5 T, a rather long TE (roughly 40 msec) is required for this cancellation to become significant, leading to enhanced susceptibility artifacts and a long data acquisition time. In this study, we examine the utility of incorporating a clinically available T1 reducing contrast agent, Omniscan (Sanofi Winthrop Pharmaceuticals, NY, NY), with the HRBV imaging approach to reduce susceptibility artifacts and imaging time while maintaining the visibility of cerebral veins. Using a double-dose injection of Omniscan, we were able to reduce TE from 40 to 25 msec. This led to a decrease in TR from 57 to 42 msec, allowing a 26% reduction in data acquisition time while maintaining the visibility of cerebral venous vessels and reducing susceptibility artifacts. J. Magn. Reson. Imaging 1999;10:118-123, 1999.

Figure 1

A comparison of images from two volunteers pre-and post-contrast. The first volunteer received a single dose of contrast agent. There are some improvements in venous vessel visualization from pre-contrast (a) to post-contrast (b). The second volunteer, on the other hand, received a double dose of contrast agent. A substantial improvement in the venous vessel visualization (arrow) is observed from pre-contrast (c) to post-contrast (d). All images were acquired with a TE of 40 msec.

Figure 2

HRBV images from a subset of the multi-echo sequence are shown to demonstrate the signal cancellation for three different TEs (17.5, 28.7, and 39.9 msec for images from left to right in each row) pre-contrast (row a) and three time points post-contrast (rows b–d). Images in row b were collected immediately after the injection of contrast agent, row c 10 minutes later, and row d 20minutes later. There is little change in venous vessel visualization during the first 30 minutes after the injection of contrast agent.

Figure 3

A comparison of HRBV with different TEs pre- (a–c) and post-contrast (d–f) with the single-echo 3D sequence. The TE values are 40, 30, and 25 msec for images from left to right in each row.